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1da177e4 LT |
1 | /* $Id: uaccess.h,v 1.11 2003/10/13 07:21:20 lethal Exp $ |
2 | * | |
3 | * User space memory access functions | |
4 | * | |
5 | * Copyright (C) 1999, 2002 Niibe Yutaka | |
6 | * Copyright (C) 2003 Paul Mundt | |
7 | * | |
8 | * Based on: | |
9 | * MIPS implementation version 1.15 by | |
10 | * Copyright (C) 1996, 1997, 1998 by Ralf Baechle | |
11 | * and i386 version. | |
12 | */ | |
13 | #ifndef __ASM_SH_UACCESS_H | |
14 | #define __ASM_SH_UACCESS_H | |
15 | ||
16 | #include <linux/errno.h> | |
17 | #include <linux/sched.h> | |
18 | ||
1da177e4 LT |
19 | #define VERIFY_READ 0 |
20 | #define VERIFY_WRITE 1 | |
21 | ||
1da177e4 LT |
22 | /* |
23 | * The fs value determines whether argument validity checking should be | |
24 | * performed or not. If get_fs() == USER_DS, checking is performed, with | |
25 | * get_fs() == KERNEL_DS, checking is bypassed. | |
26 | * | |
27 | * For historical reasons (Data Segment Register?), these macros are misnamed. | |
28 | */ | |
29 | ||
30 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | |
1da177e4 | 31 | |
2991be72 PM |
32 | #define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFFUL) |
33 | #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) | |
34 | ||
35 | #define segment_eq(a,b) ((a).seg == (b).seg) | |
1da177e4 | 36 | |
2991be72 PM |
37 | #define __addr_ok(addr) \ |
38 | ((unsigned long)(addr) < (current_thread_info()->addr_limit.seg)) | |
1da177e4 LT |
39 | |
40 | #define get_ds() (KERNEL_DS) | |
41 | ||
42 | #if !defined(CONFIG_MMU) | |
43 | static inline mm_segment_t get_fs(void) | |
44 | { | |
45 | return USER_DS; | |
46 | } | |
47 | ||
48 | static inline void set_fs(mm_segment_t s) | |
49 | { | |
50 | } | |
51 | ||
52 | /* | |
53 | * __access_ok: Check if address with size is OK or not. | |
54 | * | |
55 | * If we don't have an MMU (or if its disabled) the only thing we really have | |
56 | * to look out for is if the address resides somewhere outside of what | |
57 | * available RAM we have. | |
58 | * | |
59 | * TODO: This check could probably also stand to be restricted somewhat more.. | |
60 | * though it still does the Right Thing(tm) for the time being. | |
61 | */ | |
62 | static inline int __access_ok(unsigned long addr, unsigned long size) | |
63 | { | |
64 | extern unsigned long memory_start, memory_end; | |
65 | ||
66 | return ((addr >= memory_start) && ((addr + size) < memory_end)); | |
67 | } | |
68 | #else /* CONFIG_MMU */ | |
2991be72 PM |
69 | #define get_fs() (current_thread_info()->addr_limit) |
70 | #define set_fs(x) (current_thread_info()->addr_limit = (x)) | |
1da177e4 LT |
71 | |
72 | /* | |
73 | * __access_ok: Check if address with size is OK or not. | |
74 | * | |
75 | * We do three checks: | |
76 | * (1) is it user space? | |
77 | * (2) addr + size --> carry? | |
2991be72 | 78 | * (3) addr + size >= 0x80000000 (PAGE_OFFSET) |
1da177e4 LT |
79 | * |
80 | * (1) (2) (3) | RESULT | |
81 | * 0 0 0 | ok | |
82 | * 0 0 1 | ok | |
83 | * 0 1 0 | bad | |
84 | * 0 1 1 | bad | |
85 | * 1 0 0 | ok | |
86 | * 1 0 1 | bad | |
87 | * 1 1 0 | bad | |
88 | * 1 1 1 | bad | |
89 | */ | |
90 | static inline int __access_ok(unsigned long addr, unsigned long size) | |
91 | { | |
92 | unsigned long flag, tmp; | |
93 | ||
94 | __asm__("stc r7_bank, %0\n\t" | |
95 | "mov.l @(8,%0), %0\n\t" | |
96 | "clrt\n\t" | |
97 | "addc %2, %1\n\t" | |
98 | "and %1, %0\n\t" | |
99 | "rotcl %0\n\t" | |
100 | "rotcl %0\n\t" | |
101 | "and #3, %0" | |
102 | : "=&z" (flag), "=r" (tmp) | |
103 | : "r" (addr), "1" (size) | |
104 | : "t"); | |
105 | ||
106 | return flag == 0; | |
107 | } | |
108 | #endif /* CONFIG_MMU */ | |
109 | ||
110 | static inline int access_ok(int type, const void __user *p, unsigned long size) | |
111 | { | |
112 | unsigned long addr = (unsigned long)p; | |
113 | return __access_ok(addr, size); | |
114 | } | |
115 | ||
1da177e4 LT |
116 | /* |
117 | * Uh, these should become the main single-value transfer routines ... | |
118 | * They automatically use the right size if we just have the right | |
119 | * pointer type ... | |
120 | * | |
121 | * As SuperH uses the same address space for kernel and user data, we | |
122 | * can just do these as direct assignments. | |
123 | * | |
124 | * Careful to not | |
125 | * (a) re-use the arguments for side effects (sizeof is ok) | |
126 | * (b) require any knowledge of processes at this stage | |
127 | */ | |
128 | #define put_user(x,ptr) __put_user_check((x),(ptr),sizeof(*(ptr))) | |
129 | #define get_user(x,ptr) __get_user_check((x),(ptr),sizeof(*(ptr))) | |
130 | ||
131 | /* | |
132 | * The "__xxx" versions do not do address space checking, useful when | |
133 | * doing multiple accesses to the same area (the user has to do the | |
134 | * checks by hand with "access_ok()") | |
135 | */ | |
136 | #define __put_user(x,ptr) \ | |
137 | __put_user_nocheck((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr))) | |
138 | #define __get_user(x,ptr) \ | |
139 | __get_user_nocheck((x),(ptr),sizeof(*(ptr))) | |
140 | ||
141 | struct __large_struct { unsigned long buf[100]; }; | |
142 | #define __m(x) (*(struct __large_struct *)(x)) | |
143 | ||
144 | #define __get_user_size(x,ptr,size,retval) \ | |
145 | do { \ | |
146 | retval = 0; \ | |
147 | switch (size) { \ | |
148 | case 1: \ | |
149 | __get_user_asm(x, ptr, retval, "b"); \ | |
150 | break; \ | |
151 | case 2: \ | |
152 | __get_user_asm(x, ptr, retval, "w"); \ | |
153 | break; \ | |
154 | case 4: \ | |
155 | __get_user_asm(x, ptr, retval, "l"); \ | |
156 | break; \ | |
157 | default: \ | |
158 | __get_user_unknown(); \ | |
159 | break; \ | |
160 | } \ | |
161 | } while (0) | |
162 | ||
163 | #define __get_user_nocheck(x,ptr,size) \ | |
164 | ({ \ | |
165 | long __gu_err, __gu_val; \ | |
166 | __get_user_size(__gu_val, (ptr), (size), __gu_err); \ | |
167 | (x) = (__typeof__(*(ptr)))__gu_val; \ | |
168 | __gu_err; \ | |
169 | }) | |
170 | ||
e96636cc | 171 | #ifdef CONFIG_MMU |
1da177e4 LT |
172 | #define __get_user_check(x,ptr,size) \ |
173 | ({ \ | |
174 | long __gu_err, __gu_val; \ | |
175 | switch (size) { \ | |
176 | case 1: \ | |
177 | __get_user_1(__gu_val, (ptr), __gu_err); \ | |
178 | break; \ | |
179 | case 2: \ | |
180 | __get_user_2(__gu_val, (ptr), __gu_err); \ | |
181 | break; \ | |
182 | case 4: \ | |
183 | __get_user_4(__gu_val, (ptr), __gu_err); \ | |
184 | break; \ | |
185 | default: \ | |
186 | __get_user_unknown(); \ | |
187 | break; \ | |
188 | } \ | |
189 | \ | |
190 | (x) = (__typeof__(*(ptr)))__gu_val; \ | |
191 | __gu_err; \ | |
192 | }) | |
193 | ||
194 | #define __get_user_1(x,addr,err) ({ \ | |
195 | __asm__("stc r7_bank, %1\n\t" \ | |
196 | "mov.l @(8,%1), %1\n\t" \ | |
197 | "and %2, %1\n\t" \ | |
198 | "cmp/pz %1\n\t" \ | |
199 | "bt/s 1f\n\t" \ | |
200 | " mov #0, %0\n\t" \ | |
201 | "0:\n" \ | |
202 | "mov #-14, %0\n\t" \ | |
203 | "bra 2f\n\t" \ | |
204 | " mov #0, %1\n" \ | |
205 | "1:\n\t" \ | |
206 | "mov.b @%2, %1\n\t" \ | |
207 | "extu.b %1, %1\n" \ | |
208 | "2:\n" \ | |
209 | ".section __ex_table,\"a\"\n\t" \ | |
210 | ".long 1b, 0b\n\t" \ | |
211 | ".previous" \ | |
212 | : "=&r" (err), "=&r" (x) \ | |
213 | : "r" (addr) \ | |
214 | : "t"); \ | |
215 | }) | |
216 | ||
217 | #define __get_user_2(x,addr,err) ({ \ | |
218 | __asm__("stc r7_bank, %1\n\t" \ | |
219 | "mov.l @(8,%1), %1\n\t" \ | |
220 | "and %2, %1\n\t" \ | |
221 | "cmp/pz %1\n\t" \ | |
222 | "bt/s 1f\n\t" \ | |
223 | " mov #0, %0\n\t" \ | |
224 | "0:\n" \ | |
225 | "mov #-14, %0\n\t" \ | |
226 | "bra 2f\n\t" \ | |
227 | " mov #0, %1\n" \ | |
228 | "1:\n\t" \ | |
229 | "mov.w @%2, %1\n\t" \ | |
230 | "extu.w %1, %1\n" \ | |
231 | "2:\n" \ | |
232 | ".section __ex_table,\"a\"\n\t" \ | |
233 | ".long 1b, 0b\n\t" \ | |
234 | ".previous" \ | |
235 | : "=&r" (err), "=&r" (x) \ | |
236 | : "r" (addr) \ | |
237 | : "t"); \ | |
238 | }) | |
239 | ||
240 | #define __get_user_4(x,addr,err) ({ \ | |
241 | __asm__("stc r7_bank, %1\n\t" \ | |
242 | "mov.l @(8,%1), %1\n\t" \ | |
243 | "and %2, %1\n\t" \ | |
244 | "cmp/pz %1\n\t" \ | |
245 | "bt/s 1f\n\t" \ | |
246 | " mov #0, %0\n\t" \ | |
247 | "0:\n" \ | |
248 | "mov #-14, %0\n\t" \ | |
249 | "bra 2f\n\t" \ | |
250 | " mov #0, %1\n" \ | |
251 | "1:\n\t" \ | |
252 | "mov.l @%2, %1\n\t" \ | |
253 | "2:\n" \ | |
254 | ".section __ex_table,\"a\"\n\t" \ | |
255 | ".long 1b, 0b\n\t" \ | |
256 | ".previous" \ | |
257 | : "=&r" (err), "=&r" (x) \ | |
258 | : "r" (addr) \ | |
259 | : "t"); \ | |
260 | }) | |
e96636cc YS |
261 | #else /* CONFIG_MMU */ |
262 | #define __get_user_check(x,ptr,size) \ | |
263 | ({ \ | |
264 | long __gu_err, __gu_val; \ | |
265 | if (__access_ok((unsigned long)(ptr), (size))) { \ | |
266 | __get_user_size(__gu_val, (ptr), (size), __gu_err); \ | |
267 | (x) = (__typeof__(*(ptr)))__gu_val; \ | |
268 | } else \ | |
269 | __gu_err = -EFAULT; \ | |
270 | __gu_err; \ | |
271 | }) | |
272 | #endif | |
1da177e4 LT |
273 | |
274 | #define __get_user_asm(x, addr, err, insn) \ | |
275 | ({ \ | |
276 | __asm__ __volatile__( \ | |
277 | "1:\n\t" \ | |
278 | "mov." insn " %2, %1\n\t" \ | |
279 | "mov #0, %0\n" \ | |
280 | "2:\n" \ | |
281 | ".section .fixup,\"ax\"\n" \ | |
282 | "3:\n\t" \ | |
283 | "mov #0, %1\n\t" \ | |
284 | "mov.l 4f, %0\n\t" \ | |
285 | "jmp @%0\n\t" \ | |
286 | " mov %3, %0\n" \ | |
287 | "4: .long 2b\n\t" \ | |
288 | ".previous\n" \ | |
289 | ".section __ex_table,\"a\"\n\t" \ | |
290 | ".long 1b, 3b\n\t" \ | |
291 | ".previous" \ | |
292 | :"=&r" (err), "=&r" (x) \ | |
293 | :"m" (__m(addr)), "i" (-EFAULT)); }) | |
294 | ||
295 | extern void __get_user_unknown(void); | |
296 | ||
297 | #define __put_user_size(x,ptr,size,retval) \ | |
298 | do { \ | |
299 | retval = 0; \ | |
300 | switch (size) { \ | |
301 | case 1: \ | |
302 | __put_user_asm(x, ptr, retval, "b"); \ | |
303 | break; \ | |
304 | case 2: \ | |
305 | __put_user_asm(x, ptr, retval, "w"); \ | |
306 | break; \ | |
307 | case 4: \ | |
308 | __put_user_asm(x, ptr, retval, "l"); \ | |
309 | break; \ | |
310 | case 8: \ | |
311 | __put_user_u64(x, ptr, retval); \ | |
312 | break; \ | |
313 | default: \ | |
314 | __put_user_unknown(); \ | |
315 | } \ | |
316 | } while (0) | |
317 | ||
318 | #define __put_user_nocheck(x,ptr,size) \ | |
319 | ({ \ | |
320 | long __pu_err; \ | |
321 | __put_user_size((x),(ptr),(size),__pu_err); \ | |
322 | __pu_err; \ | |
323 | }) | |
324 | ||
325 | #define __put_user_check(x,ptr,size) \ | |
326 | ({ \ | |
327 | long __pu_err = -EFAULT; \ | |
328 | __typeof__(*(ptr)) *__pu_addr = (ptr); \ | |
329 | \ | |
330 | if (__access_ok((unsigned long)__pu_addr,size)) \ | |
331 | __put_user_size((x),__pu_addr,(size),__pu_err); \ | |
332 | __pu_err; \ | |
333 | }) | |
334 | ||
335 | #define __put_user_asm(x, addr, err, insn) \ | |
336 | ({ \ | |
337 | __asm__ __volatile__( \ | |
338 | "1:\n\t" \ | |
339 | "mov." insn " %1, %2\n\t" \ | |
340 | "mov #0, %0\n" \ | |
341 | "2:\n" \ | |
342 | ".section .fixup,\"ax\"\n" \ | |
343 | "3:\n\t" \ | |
344 | "nop\n\t" \ | |
345 | "mov.l 4f, %0\n\t" \ | |
346 | "jmp @%0\n\t" \ | |
347 | "mov %3, %0\n" \ | |
348 | "4: .long 2b\n\t" \ | |
349 | ".previous\n" \ | |
350 | ".section __ex_table,\"a\"\n\t" \ | |
351 | ".long 1b, 3b\n\t" \ | |
352 | ".previous" \ | |
353 | :"=&r" (err) \ | |
354 | :"r" (x), "m" (__m(addr)), "i" (-EFAULT) \ | |
355 | :"memory"); }) | |
356 | ||
357 | #if defined(__LITTLE_ENDIAN__) | |
358 | #define __put_user_u64(val,addr,retval) \ | |
359 | ({ \ | |
360 | __asm__ __volatile__( \ | |
361 | "1:\n\t" \ | |
362 | "mov.l %R1,%2\n\t" \ | |
363 | "mov.l %S1,%T2\n\t" \ | |
364 | "mov #0,%0\n" \ | |
365 | "2:\n" \ | |
366 | ".section .fixup,\"ax\"\n" \ | |
367 | "3:\n\t" \ | |
368 | "nop\n\t" \ | |
369 | "mov.l 4f,%0\n\t" \ | |
370 | "jmp @%0\n\t" \ | |
371 | " mov %3,%0\n" \ | |
372 | "4: .long 2b\n\t" \ | |
373 | ".previous\n" \ | |
374 | ".section __ex_table,\"a\"\n\t" \ | |
375 | ".long 1b, 3b\n\t" \ | |
376 | ".previous" \ | |
377 | : "=r" (retval) \ | |
378 | : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \ | |
379 | : "memory"); }) | |
380 | #else | |
381 | #define __put_user_u64(val,addr,retval) \ | |
382 | ({ \ | |
383 | __asm__ __volatile__( \ | |
384 | "1:\n\t" \ | |
385 | "mov.l %S1,%2\n\t" \ | |
386 | "mov.l %R1,%T2\n\t" \ | |
387 | "mov #0,%0\n" \ | |
388 | "2:\n" \ | |
389 | ".section .fixup,\"ax\"\n" \ | |
390 | "3:\n\t" \ | |
391 | "nop\n\t" \ | |
392 | "mov.l 4f,%0\n\t" \ | |
393 | "jmp @%0\n\t" \ | |
394 | " mov %3,%0\n" \ | |
395 | "4: .long 2b\n\t" \ | |
396 | ".previous\n" \ | |
397 | ".section __ex_table,\"a\"\n\t" \ | |
398 | ".long 1b, 3b\n\t" \ | |
399 | ".previous" \ | |
400 | : "=r" (retval) \ | |
401 | : "r" (val), "m" (__m(addr)), "i" (-EFAULT) \ | |
402 | : "memory"); }) | |
403 | #endif | |
404 | ||
405 | extern void __put_user_unknown(void); | |
406 | \f | |
407 | /* Generic arbitrary sized copy. */ | |
408 | /* Return the number of bytes NOT copied */ | |
409 | extern __kernel_size_t __copy_user(void *to, const void *from, __kernel_size_t n); | |
410 | ||
411 | #define copy_to_user(to,from,n) ({ \ | |
412 | void *__copy_to = (void *) (to); \ | |
413 | __kernel_size_t __copy_size = (__kernel_size_t) (n); \ | |
414 | __kernel_size_t __copy_res; \ | |
415 | if(__copy_size && __access_ok((unsigned long)__copy_to, __copy_size)) { \ | |
416 | __copy_res = __copy_user(__copy_to, (void *) (from), __copy_size); \ | |
417 | } else __copy_res = __copy_size; \ | |
418 | __copy_res; }) | |
419 | ||
420 | #define __copy_to_user(to,from,n) \ | |
421 | __copy_user((void *)(to), \ | |
422 | (void *)(from), n) | |
423 | ||
424 | #define __copy_to_user_inatomic __copy_to_user | |
425 | #define __copy_from_user_inatomic __copy_from_user | |
426 | ||
427 | ||
428 | #define copy_from_user(to,from,n) ({ \ | |
429 | void *__copy_to = (void *) (to); \ | |
430 | void *__copy_from = (void *) (from); \ | |
431 | __kernel_size_t __copy_size = (__kernel_size_t) (n); \ | |
432 | __kernel_size_t __copy_res; \ | |
433 | if(__copy_size && __access_ok((unsigned long)__copy_from, __copy_size)) { \ | |
434 | __copy_res = __copy_user(__copy_to, __copy_from, __copy_size); \ | |
435 | } else __copy_res = __copy_size; \ | |
436 | __copy_res; }) | |
437 | ||
438 | #define __copy_from_user(to,from,n) \ | |
439 | __copy_user((void *)(to), \ | |
440 | (void *)(from), n) | |
441 | ||
442 | /* | |
443 | * Clear the area and return remaining number of bytes | |
444 | * (on failure. Usually it's 0.) | |
445 | */ | |
446 | extern __kernel_size_t __clear_user(void *addr, __kernel_size_t size); | |
447 | ||
448 | #define clear_user(addr,n) ({ \ | |
449 | void * __cl_addr = (addr); \ | |
450 | unsigned long __cl_size = (n); \ | |
451 | if (__cl_size && __access_ok(((unsigned long)(__cl_addr)), __cl_size)) \ | |
452 | __cl_size = __clear_user(__cl_addr, __cl_size); \ | |
453 | __cl_size; }) | |
454 | ||
455 | static __inline__ int | |
456 | __strncpy_from_user(unsigned long __dest, unsigned long __user __src, int __count) | |
457 | { | |
458 | __kernel_size_t res; | |
459 | unsigned long __dummy, _d, _s; | |
460 | ||
461 | __asm__ __volatile__( | |
462 | "9:\n" | |
463 | "mov.b @%2+, %1\n\t" | |
464 | "cmp/eq #0, %1\n\t" | |
465 | "bt/s 2f\n" | |
466 | "1:\n" | |
467 | "mov.b %1, @%3\n\t" | |
468 | "dt %7\n\t" | |
469 | "bf/s 9b\n\t" | |
470 | " add #1, %3\n\t" | |
471 | "2:\n\t" | |
472 | "sub %7, %0\n" | |
473 | "3:\n" | |
474 | ".section .fixup,\"ax\"\n" | |
475 | "4:\n\t" | |
476 | "mov.l 5f, %1\n\t" | |
477 | "jmp @%1\n\t" | |
478 | " mov %8, %0\n\t" | |
479 | ".balign 4\n" | |
480 | "5: .long 3b\n" | |
481 | ".previous\n" | |
482 | ".section __ex_table,\"a\"\n" | |
483 | " .balign 4\n" | |
484 | " .long 9b,4b\n" | |
485 | ".previous" | |
486 | : "=r" (res), "=&z" (__dummy), "=r" (_s), "=r" (_d) | |
487 | : "0" (__count), "2" (__src), "3" (__dest), "r" (__count), | |
488 | "i" (-EFAULT) | |
489 | : "memory", "t"); | |
490 | ||
491 | return res; | |
492 | } | |
493 | ||
494 | #define strncpy_from_user(dest,src,count) ({ \ | |
495 | unsigned long __sfu_src = (unsigned long) (src); \ | |
496 | int __sfu_count = (int) (count); \ | |
497 | long __sfu_res = -EFAULT; \ | |
498 | if(__access_ok(__sfu_src, __sfu_count)) { \ | |
499 | __sfu_res = __strncpy_from_user((unsigned long) (dest), __sfu_src, __sfu_count); \ | |
500 | } __sfu_res; }) | |
501 | ||
502 | /* | |
503 | * Return the size of a string (including the ending 0!) | |
504 | */ | |
505 | static __inline__ long __strnlen_user(const char __user *__s, long __n) | |
506 | { | |
507 | unsigned long res; | |
508 | unsigned long __dummy; | |
509 | ||
510 | __asm__ __volatile__( | |
511 | "9:\n" | |
512 | "cmp/eq %4, %0\n\t" | |
513 | "bt 2f\n" | |
514 | "1:\t" | |
515 | "mov.b @(%0,%3), %1\n\t" | |
516 | "tst %1, %1\n\t" | |
517 | "bf/s 9b\n\t" | |
518 | " add #1, %0\n" | |
519 | "2:\n" | |
520 | ".section .fixup,\"ax\"\n" | |
521 | "3:\n\t" | |
522 | "mov.l 4f, %1\n\t" | |
523 | "jmp @%1\n\t" | |
2991be72 | 524 | " mov #0, %0\n" |
1da177e4 LT |
525 | ".balign 4\n" |
526 | "4: .long 2b\n" | |
527 | ".previous\n" | |
528 | ".section __ex_table,\"a\"\n" | |
529 | " .balign 4\n" | |
530 | " .long 1b,3b\n" | |
531 | ".previous" | |
532 | : "=z" (res), "=&r" (__dummy) | |
2991be72 | 533 | : "0" (0), "r" (__s), "r" (__n) |
1da177e4 LT |
534 | : "t"); |
535 | return res; | |
536 | } | |
537 | ||
538 | static __inline__ long strnlen_user(const char __user *s, long n) | |
539 | { | |
2991be72 | 540 | if (!__addr_ok(s)) |
1da177e4 LT |
541 | return 0; |
542 | else | |
543 | return __strnlen_user(s, n); | |
544 | } | |
545 | ||
2991be72 | 546 | #define strlen_user(str) strnlen_user(str, ~0UL >> 1) |
1da177e4 LT |
547 | |
548 | /* | |
549 | * The exception table consists of pairs of addresses: the first is the | |
550 | * address of an instruction that is allowed to fault, and the second is | |
551 | * the address at which the program should continue. No registers are | |
552 | * modified, so it is entirely up to the continuation code to figure out | |
553 | * what to do. | |
554 | * | |
555 | * All the routines below use bits of fixup code that are out of line | |
556 | * with the main instruction path. This means when everything is well, | |
557 | * we don't even have to jump over them. Further, they do not intrude | |
558 | * on our cache or tlb entries. | |
559 | */ | |
560 | ||
561 | struct exception_table_entry | |
562 | { | |
563 | unsigned long insn, fixup; | |
564 | }; | |
565 | ||
566 | extern int fixup_exception(struct pt_regs *regs); | |
567 | ||
568 | #endif /* __ASM_SH_UACCESS_H */ |